1. Field of the Invention
The invention relates generally to a cyclic process for the catalytic conversion of biomass. The process lends itself for operation on a commercial scale, as well as on pilot plant and laboratory scale. The invention further relates to an apparatus in which the simulated process can be carried out.
2. Description of the Related Art
Catalytic processes have been proposed for the catalytic conversion of biomass to, for example, liquid products such as bio-oil. Fluid bed processes are among the processes that have been proposed. Preferred prior art processes are continuous processes. Such processes have many advantages, but are not suitable for short reaction runs, as it takes some time for the reaction conditions of a continuous process to reach steady state. Also, the reaction equipment required for continuous processes is by necessity relatively large, making it less suitable for a distributed process whereby biomass conversion is carried out in close proximity of the biomass harvest site.
Accordingly, there is a need for a catalytic biomass conversion process that can be carried out in batch mode, requiring relatively small reaction equipment as compared to the equipment required for continuous processes.
There is a further need for a laboratory-scale or pilot plant scale process and apparatus in which a fluid catalytic pyrolysis process for the conversion of solid biomass material can be simulated. There is a particular need for simulating such processes on a laboratory scale, preferably requiring only gram quantities of biomass material.
Small-scale processes have been developed for simulating fluid catalytic cracking (“FCC”) of crude oil fractions. Several of these processes are operated in batch mode. The most commonly used batch process for simulating FCC is the so-called micro-activity test (“MAT”). This test is described in ASTM D-3907-86. Being a batch process MAT differs in many crucial ways from the commercial, full-scale FCC process. As a consequence, MAT's utility in predicting selectivities and yields obtained in a full-scale FCC unit are limited.
U.S. Pat. No. 5,102,628 to De Lasa discloses a “riser simulator” designed to make it possible to use a catalyst-to-oil ratio corresponding with the standard catalyst-to-oil ratio used in conventional riser reactors. The reactor can only be used for fluid feedstocks.
U.S. Pat. No. 6,069,012 to Kayser discloses a laboratory scale fluid catalytic cracking apparatus designed to emulate commercial riser cracking. The apparatus includes a reactor having a removable feed injector to facilitate changing quickly hydrocarbon contact time without varying the feed rate, diluent rates, or catalyst charge.
US Patent Application Publication 2005/0145542 discloses a cyclic process for testing FCC catalysts with resid feedstock on a small scale. In a first cycle the feed to be cracked is heated to a temperature between 50 and 500° C. The heated feed is injected into a riser reactor containing the FCC catalyst to be tested having a temperature between 500 and 800° C. An inert gas is injected into the lower end of the riser in the vicinity of the feed injection point. The feed is hereby contacted with the FCC catalyst under fluidized conditions. The feed is stripped from the FCC catalyst and the reaction product is analyzed. In a second cycle a quench liquid is injected into the riser reactor.
The small-scale processes that have been developed for emulating FCC are designed to handle liquid feedstocks.
Thus, there is a particular need for a small-scale process that reliably emulates fluid catalytic cracking of solid biomass materials. The process should be suitable for lab-scale and for pilot plant scale operation, as well as for small-scale commercial operation.